Multiple data formats may be transmitted over data lines in computer circuitry or communications systems. A receiving device or receiving user needs to know the data format of the received data to correctly decode the received data to acquire the information being transmitted. In some conventional systems, a type of communication line or circuitry line is determinative of the format of data being conveyed over that communication line or circuitry line. For example, when a Serial-ATA hard drive is connected through a cable to a computer motherboard, the circuitry on the motherboard can expect that data transferred through the cable is formatted according to the specifications of the Serial-ATA interface.
In other conventional systems that have multi-purpose data lines or communications lines, extra information is transmitted along with the data and that extra information may be used to determine the encoding of received data. When the encoding is determined, the information in the data may be acquired. Some examples of such extra information are shown in and described with reference to FIG. 1 and FIG. 2.
One example technique for including extra information is to attach a header to data. FIG. 1 is an illustration for a data format having a header attached to payloads according to the prior art. Data 102 may include a header 102A and a payload 102B; data 104 may include a header 104A and a payload 104B. The data 102 and 104 may be communicated over the same data line or communications line while being differently formatted. When a receiver receives the data 102 and 104, the receiver may examine the header 102A to identify an encoding of payload 102B and may examine the header 104A to identify an encoding of payload 104B. After identifying the encoding format indicated in header 102A, the receiver may decode the payload 102B accordingly. The headers 102A and 104A provide an indication of the encoding of the data, however the headers 102A and 104A consume transmission resources without conveying substantive information. Instead, transmission resources are consumed to send the necessary control information. Thus, the use of headers in this manner is inefficient. When the payload is audio data, the use of the headers reduces available bandwidth for audio data and can decrease the quality of the audio.
Another example technique for including extra information is to convey the extra information in a control line separate from the data line. FIG. 2 is an illustration for a data format having control data attached to payloads according to the prior art. A sending device 112A may transmit information to a receiving device 112B over data lines 114A and control lines 114B. The substantive information may be encoded as payloads 116 and transmitted over the data lines 114A. Information indicative of an encoding of the payloads 116 may be transmitted as control information 118 over the control lines 114B. The receiving device 112B uses the data encoding indication in the control information 118 to decode the payload 116. The separation of control information 118 from the payload 116 allows substantive information to be transmitted quicker over the data lines 114A without the need for the header 102A of FIG. 1. However, the additional control lines 114B require additional space on a circuit board or additional communications lines. Furthermore, the receiving device 112B requires additional pin connections for the control lines 114B and the receiving device 112B requires a manner for synchronizing the control information 118 with the payloads 116.
Each of these conventional solutions is a technique for allowing different encodings of data over a data line or communications line. One example situation that requires such a capability is an audio device supporting multiple audio formats. For example, an audio system may accept digital audio as either pulse code modulated (PCM) digital data or direct stream digital (DSD) digital data. Rather than include two separate data paths and switch between the two data paths, DSD digital data may be transmitted as DSD over PCM (DoP) data, in which the DSD data is transmitted as if the DSD data was PCM data. The receiving audio system must be informed when the incoming data is DSD data and when the data is PCM data. That indication would conventionally be provided using one of the conventional techniques described above. However, providing that extra information can degrade system performance and increase system cost due to required space.
Shortcomings mentioned here are only representative and are included simply to highlight that a need exists for improved electrical components, particularly for data transmission and processing employed in consumer-level devices, such as personal media devices (e.g., smart phones). Embodiments described herein address certain shortcomings but not necessarily each and every one described here or known in the art. Furthermore, embodiments described herein may present other benefits than, and be used in other applications than, those of the shortcomings described above.